vSPD overview

vSPD stands for vectorised Scheduling, Pricing and Dispatch. The vSPD model is a precise replica of SPD. It is written and solved using the
GAMS software and is based on the published SPD formulation.

vSPD takes advantage of the computational efficiency of modern linear programming and mixed integer programming solvers through vectorisation of some schedules prior to solving. Vectorisation involves reformulating the sequential, independent trading period problems as a single optimization and therefore requires just a single solve for the entire vectorised set of schedules. In other words, vSPD is generally configured to solve an entire day, or 48 trading periods, at once.

The input data for vSPD is provided in the form of GDX files. Daily GDX files for use in vSPD can be found in Datasets.

vSPD output is generated as a collection of GDX and CSV files that report on the key model outputs such as generation, prices, branch flows and reserves. Some inputs to the model, for example load, are also included in the output reports.

An online version of vSPD called vSPD-online is available for use from within a web browser and without the need to learn GAMS or acquire the GAMS software. Under the hood, vSPD-online is identical to vSPD, it uses the same input GDX files, and will generate an identical solution to an equivalently configured run of vSPD. However, the range of what-if scenarios that can be explored, while still quite substantial, is less than can be undertaken by users that have access to vSPD.

Audit and certificate of compliance

vSPD is regularly audited by the same independent auditors contracted by the system operator to audit SPD each time a change to the SPD formulation is implemented.

The most recent audit of vSPD was undertaken in August 2019 by Robinson Bowmaker Paul (RBP). The RBP approach to testing and their statement of vSPD's fitness for use are explained in the vSPD certificate of compliance.

vSPD certificate of compliance

Download and install vSPD

Development of vSPD is ongoing. Soon after vSPD has been audited, it is likely to be modified in some way although at all times it will replicate SPD for all published schedules. We don’t have vSPD audited after every modification; some changes are quite trivial. Version 3.0.4 of vSPD is consistent with commit 967c236 on the vSPD GitHub repository.